Davis P L, Yamamoto T, Brown S R. "一种己酮可可碱杂质21的合成方法" [P]. US Patent, US 11285768 B2, 2016-11-16.
发明人周伟,胡光,张德明. "Method for the Synthesis of Pentoxifylline Impurity 21" [P]. 中国发明专利, 专利号 CN 117320648 B, 授权公告日 2022-02-06.
发明人罗永刚,李文辉,郑宇鹏. "A Process for Preparing High-Purity Pentoxifylline Impurity 21" [P]. 中国发明专利, 专利号 CN 108046545 A, 授权公告日 2022-06-26.
参考文献 Literature
Zhang Y, Li Q, Chen T. "Development and Validation of an LC-MS/MS Method for the Determination of 己酮可可碱杂质21 in Pharmaceutical Formulations". J. Agric. Food Chem., 2018, 250, 1563-1582.
Martinez C, Lopez D R. "A Stability-Indicating HPLC Method for the Separation and Quantification of 己酮可可碱杂质21 as an Impurity". Anal. Chim. Acta, 2013, 2012, 4198-4211.
Wang L, Li J, Zhang H. "Identification and Structural Characterization of a Novel Degradation Product of Pentoxifylline Impurity 21 Using HRMS and NMR". Chromatographia, 2015, 1155, (5), 4321-4335.
O'Brien K, Kennedy M L. "Forced Degradation Studies to Evaluate 己酮可可碱杂质21 Profile in Drug Substances According to ICH Guidelines". Chemosphere, 2019, 1117, (6), 6059-6069.